Gamma-lactonecarboxylic acid derivatives and their use as antibacterial agents or intermediates

Abstract

A compound represented by formula (I): ##STR1## wherein R 1 is an organic residue through a carbon atom, R 2 is a carboxyl group which may be esterified or amidated, and X is an oxygen atom, or a sulfur atom which may be oxidized, or a salt thereof, which is useful as antibacterial agent or intermediate for synthesizing the same, and a process for preparing the same.

What we claim is: 
     
       1. A compound of the formula ##STR11## wherein R 1  is (1) C 1-6  alkyl which is unsubstituted or is substituted by pyridyl, thienyl, furyl or phenyl, (2) C 4-6  cycloalkyl, (3) phenyl which is unsubstituted or is substituted by halogen, nitro, cyano, C 1-3  or C 1-3  alkoxyl, (4) pyridyl which is unquaternized or quaternized and which is unsubstituted or is substituted by methyl, or (5) imidazolyl which is unsubstituted or is substituted by methyl; R 2  is a carboxyl group which is free or is esterified by C 1-10  alkyl, benzyl, nitrobenzyl or benzhydryl; and X is an oxygen atom or a sulfur atom which is unoxidized or is oxidized, or a salt thereof. 
     
     
       2. A compound according to claim 1 in which R 1  is 2-pyridylmethyl, 4-pyridylmethyl, 2-pyridyl, 4-pyridyl, 4-chlorophenyl, phenyl or 4-nitrobenzyl; R 2  is a carboxyl group which is free or is esterified by benzyl, nitrobenzyl, benzyhydryl or C 1-10  alkyl; and X is --O--, --S--, --SO-- or --SO 2 , or a salt thereof. 
     
     
       3. A compound of claim 1 in which R 1  is 2-pyridyl or 4-pyridyl which is unquaternized or is quaternized with C 1-3  alkyl and halogen. 
     
     
       4. A compound of claim 1 in which X is sulfur atom. 
     
     
       5. A compound of claim 1 in which is benzyl 2-phenylthio-5-oxo-2-tetrahydrofurancarboxylate, methyl 2-phenylthio-5-oxo-2-tetrahydrofurancarboxylate or benzyl 2-(4-chlorophenyl)thio-5-oxo-2-tetrahydrofurancarboxylate.